Throughput abilities or passives don't really matter much, since Holy never feels weak. You just cast more spells if that is the case.
Arcane Torrent used to be OP due to it's very high mana returns, but it's hardly noticeable after the nerf. Even though it mathematically equates to a whole lot of MP5, I just cannot say I feel its impact anymore. Think of it as the mana counterpart of HW: Sanctuary.

The pandaren racial is pretty good though. If you want to min-max, it's not a bad choice.

I would say stick with Pandarian, that sweet 300 int bonus from extended food bonus is about the best you can get from racial bonuses.

Although if you really (and I mean badly) struggle with mana there is always Belf for arcane torrent.
Otherwise its goblin; 1% haste is always 1% haste, the rest are kinda meeh (from a pve perspective).

I'd probably stick with Pandaren - Epicurean doubles the benefit of stat food, extra Intellect or Spirit can't hurt in a dungeon or raid. Belf's are good too, but its been a LONG time since I played as one, let alone as a Belf Priest.

Originally Posted by Boubouille

[12:07:45] <+Radux> i think Bibi should post a super passive agressive message in there. like "OH NO LOVE FOR BIBI. I SEE HOW IT IS. YOU'RE WELCOME FOR CREATING THE SITE. CARRY ON."

OH NO LOVE FOR BIBI. I SEE HOW IT IS. YOU'RE WELCOME FOR CREATING THE SITE. CARRY ON.

If you are horde, Blood Elves are clear winners for regen. If you are alliance, Humans, Gnomes and Pandarens are equal if all you're concerned about is regen. The pandaren's racial also works with intellect, so you have a choice between regen and throughput.